Plunger-operating mechanism for blindstitch sewing machines



7 June 8 1926. 1,588,135

c. w. MUELLER PLUNGER OPERATING MECHANISM FOR BLINDSTITCH SEWING MACHINES Filed Oct. 21, 1924 5 Sheets-Sheet 1 June 8 1926; 1,588,135

' c. w. MUELLER PLUNGER OPERATING MECHANISM FOR BLINDSTITCH SEWING MACHINES Filed Oct. 21, 1924 5 Sheets-Sheet 2 June 8 1926. 1,588,135

c. w. MUELLER PLUNGER OPERATING MECHANISM FOR BLINDSIITCH SEWINGMACHINES Filed Oct. '21, 1924 5 Sheets-Sheet 5 June 8 1926. 7 1,588,135

' c. w. MUELLER PLUNGER OPERATING MECHANISM FOR BLINDSTITCH SEWING MACHINES Filed Oct. 21, 1924 5 Sheets$heet '4 em m,

June 8 1926. 1588 135 c. w. MUELLER v I PLUNGER OPERATING MECHANISM FOR BLINDS'EITCH SEWING MACHINES Filed Oct. 21, 1924 5 Sheets-Sheet 5 gwuenkoz Patented June 8, 192 6.

UNITED STATES,

PATENT OFFICE.

CHARLES w. MUELLER, on em. LOUIS, anssoum, assrdnon 'ro 'nn'w rsmvrsmm s'rrrcn micnmn 00., or an LOUIS, mssonnr, a conrona'rxon or manna PLUNGER-OPERATING MECHANISM FOR BLINDSTITCH SEWING no Application filed October 21, 1924. Serial 1%. 744,988.

This invention relates to new and useful improvements in blind stitch sewing. ma-

chines generally, although more particularly I to project a node of the body abric into the path of the needle in advance of alternate oscillations of the needle whereby the latter willon said alte both the body fabric and the fell. In felling the bottoms of trousers and other tubular articles, it is desirable to employ a machine-having a lower armaround which the tubular work may be positioned and to employ readily accesible means for ad'usting vertically the bodily position 0 oscillation of the plunger in order to predetermine the'dcpth of the needle penetration in the material. It is also desirable to provide means for yieldably supporting the plunger whereb the same will during its'upward or wor positioning movement, become automatically relieved upon the passage under the presser foot of seams or other thick portions of the article being felled.

One of the principal objects of my invenv tion is, therefore, to provide a blind stitch sewing machine includin a standard provided with a tubular Wor arm of relatively small diameter and having a plunger operating at the free end thereof with driving connections extending along the arm to the' standard, and means located at a point remote from the free end of the arm and beyond the work being felled for adjusting the of fabric, will become automatically relieved, I

thus maintaining a uniform depth of needle netration in the fabric and also avoidmg the choking of the machine and the damagmgof the material.

te oscillations engage 'line A further object of the invention to provide an oscillatory plunger lever and a fulcrum lever with an operatin connection therebetween, and means for a justing the angular positionof the fulcrum lever to vary the vertical position of bodil oscillation of the plunger lever to pred etermine the depth of needle penetration in the fabric being felled.

With the above and other objects in view which will more readily appear as the nature of the invention is better understood, the same consists in the novel construction, combination and arrangementof parts here:

inafter more fully described, illustrated and claimed.

In" the accgmpan ing drawings which 7 the p unger and its operating mechanism,

in the lower arm 5 is an enlarged sectional view of Figure 6 is a sectional view taken on the line 66 of Figure 5, and

of Figure 5.

Like reference numerals designate corresponding .parts ures of the din Although my invention is especially applicable to blind stitch sewing machines of the Lewis type andI have soillustrated the same, it willv be apparent that my invention is capable of use in connection with other types of machines.

In the drawings, the sewing machine comprises a supporting standard 5 having upper 7 is a sectional view takenon the throughout the several figand lower arms 6 and 7 connected thereto.

A stitching head 8 which is dispo the free end of the lower arm 7 is supported from the free end of the upper arm 6. This stitching head includes a needle mechanism sed above which forms the subject matter of. my conding application filed October 21, 1924, er, No. 744,984. The stitching head includes a stationary presser foot 9 having the usual work receiving opening formed therein, a needle 11 which oscillates across the usual opening in a plane preferably at a slight angle to the line of feed and which is also given a lateral or shogging movement, and a complemental stitch forming mechanism such as a rotary book 12, the needle and hook being actuated from a main drivin shaft 13 journaled in the upper arm 6. It is believed that further description of the stitching will be unnecessary as it, per se, forms no part of the present invention.

Cooperating with the under face of the stationary presser foot is a feed dog14 for intermittently feeding the fabric passed the stitch forming mechanism, and a work clamp 15 which intermittently clamps the work against the foot when the feed dog-is idle whereby the work will be retained against movement while the needle 11 enters and remains in the work, the clamp being released and. the feed dog functioningwhile the needle is out of the work.

The-feed dog 14 is of the 4-motion type, that is, forward and backward and up and down movements are imparted thereto.

The backward and forward movement of the feed dog is obtained through the medium of a rock shaft 16 which I term the feed travel shaft and the up and down movement of the feed dog is obtained from a rock shaft 17 which I term the feed lift shaft. These rock shafts 16 and 17 extend longitudinally within the flower arm 7 and have their right hand ends journaled in bearings forined in a depending lug 18 and their left hand ends journaled in I bearings formedin a block 19 located at the 40 left hand end of the lower arm 7 and formed integral therewith. Fixed to the outer end of the feed travel shaft 16 is a rock arm 20 and pivotally connecting theouter end of this rock arm and the forwardextremity of the feed dog 14 is a link 21. The rock arm 20 extends in a general horizontal direction. Thus upon movement of the rock arm 20 the link 21 will impart backward and forward movements to the feed dog 14. The feed dog 14 is pivotally connected as at 22 tothe-uper end of asubstantially vertically disposed ink 23, the lower end ofsaid link being pivotally connected as at 24 to the horizontal arm 25 (if a bell crank lever 26, the yertical arm 27 of said bell crank lever being pivotally connected as at 28 to one end of a link 29, the other end of said link 29 being pivotally connected as at30 to the outer end of a vertically disposed rock arm 31 fixed to the feed lift shaft 17. In order to retain the feed surface of the feed dog in a substantially horizontal plane during the feeding movements thereof, I provide a spring 32 which is connected between a pin 33 on the link 23 and a pendent tail 34 fixed to the feed dog 14. It will, therefore, beobserved that-upon rocking movement of the feed lift siidingv movements in a bore formed in the block 19, and this block-is formed with a seat 38 for receiving and limiting the up-' ward movement of the carrier. This carrier shaft 17 the vertlcal link 23 will be bodily is normally held in itshighest position by- -means of a flat spring 39, the inner end of which is rlgidly secured to the arm 7 and the outer end thereof is disposedto the carrier so as to yieldabfy hold the latter in its highest position. The upper end of the post 37 carries a pair of rearwardly projecting arms 40-40 between which is pivoted as at 41 the work clamp 15.

From the foregoing it will be observed that when the feed dog 14 is elevated toits highest position, the fulcrum 35 of the bell crank lever 26 is. then shifted to the pivot 24,

and consequently the last part of the rocking.

movement of the crank arm 31 will cause the bell crank lever 26 to be moved downwardly about its fulcrum 24 thus lowering the work clamp 15. The parts are so timed that the work'clamp is lowered prior to the feeding movement of the feed dog. The reverse order of movement will take'place at substantially the time when the eed dog reaches 2 the end of its feeding stroke, thus causing,

. the clamp to engage the fabric and clamp th'elatter against the presser foot 9 prior to the time the feed dog begins its downward movement.

In order to rock the feed travel shaft 16 and the feed lift shaft 17 I have provided a main shaft 13 witheccentrics 42 and 43 respectively. A connection rod 44 has its upper end engageable with'the eccentric 42' and has its lower end pivotally connected as at 45 to a rock arm 46 fixed to said shaft 16. A connection rod 47 has its upper end engageable with the eccentric 43 land has its lower end pivotally connected with a rock arm 49fixed to the shaft 17 It will be noted that the connection rods 44,and 47are disor standard 5 of the needle thread loop therethrough. In order to bring about this crimping operation, I have provided a plunger which is located within the arm 7 and is actuated from the main shaft 13 by a mechanism The arm 51 of the plunger'extends in a g eral horizontal direction and the outer end portion54 thereof extends upwardly at substantially right angles to the arm 51 and constitutes the plunger proper. The plunger 50 is oscillated about its fulcrum 52 through the medium of a toggle connection consisting of a link 55 and a link '56. These links extend below the plunger 50 and the upper end of the link 55 ispiv otally connected as at 57 to the plunger. The two links 55 and 56 are pivotally connected. as at 58. The lower end of the link 56 is pivotally connected as at 59 to a fulcrum lever 60 which extends longitudinally of the arm 7. .The fulcrum lever 60 is, of course, disposed under the plunger 50 and is fulcrumed at its outer end as at 61 .to

' the block 19. The inner end of the fulcrum lever 60 is limited in its upward movement by means of a depending'stop 62 fixed to the arm 7. A coil spring63 as its upper 7 end connected to the arm 7 and its lower end to the fulcrum lever 60. Thus the fulcrum lever is normally held in ieldable contact with the stop 62. In or er to positively adjust the position of the fulcrum lever 60 .relative to the stop 67 I have provided the lever 60 with an adjusting screw 64 which cooperates with said stop. This screw 64 is link 56 of said toggle.

provided with a head having a knurled edge and a spring latch'65 cooperates with said knurled edge to retain the screw in an adjusted position.

:In order to oscillate the plunger 50 through the medium of the toggle links 55 and 56, I have journaled in the standard 5 a rotary shaft 66 which is-driven from the main shaft 13 by a one-'to-two gear coupling 67 whereby said shaft 66 will be rotated once during every two revolutions of the main shaft. Fixed to the lower end of the shaft. 66. is a cam 68, the under surface thereof being formed with a cam ,groove 69. Located in this cam groove 69 is a roller .70 which is carried by one end of the bell cranklever 71 said bell crank lever being fulcrumed .as at 72 upon the standard 5.,

The other arm of the bell crank .lever is pivotally connected'as at 73 to the inner end. of. aconnection rod 74 which extends lengthwise ofthe arm 7 and has its outer end pivotally connected as at 75 to the -From the foregoing it will be observed that because of the two-to-one coupling 67 the plunger, 50 will be oscillated during every other reciprocation of the needle. The parts areso timed that the plunger will be elevated prior to the penetrating stroke of the needle so as to project a node :of

fabric into the path of said needle and by means of the cam 68 the plunger will be retained in its elevated position during the entire time the needle is in the node of inaterial. Inorder to predetermine the depth v of needle, penetration in said node, the fulcrum lever 60 may be adjusted by the screw 64'. Thus -by lowering the fulcrumlever 60 the vertical bodily position of oscillation of the'plunger will be correspondingly lowered and, therefore, the depth of needle penetration in the material will be de-i creased. bhould'it be desirable to increase thedepthpf needle penetration in the material the fulcrum lever 60 is raised by releasing the adjusting screw 64, the spring 63 causing the leverto remain either in direct contact with the stop 62 or in contact with said stop-through the medium of the screw. When seams or other thick portions of material are fed past the stitching head the same depth of needle penetration will be maintained owing to the fact that the plunger during its upward travel will meet 7 Y the resistance of the fabric, due to the presser foot being fixed, and consequently the upward movement of the plunger will be limited. This limitation of the upward movement is compensated for by reason of the fulcrum lever-'60 being yieldably supported by the spring 63 and consequently when the resistance of the material is thus met. by the plunger, the movement of the toggle will be continued to its maximum ex-' tent thus forcing down the fulcrum lever v 60 against the'tension of the spring 63.-

The adjusting screw 64 is located at a point remotefrom the line of feed and consequently access may be readily had to this adjusting screw while tubular work is being stitched.

I claim: 7

1. In a blind stitch sewin machine, the

ard, an upper arm and a lower tubular arm, of a stitching head carried by the upper arm, a' presser foot fixed to the stitchm head 'and formed with a work receiving opening, an oscillatory plunger lever extending lengthwise within said lower arm and having its inner end pivoted thereto, the free end of the plunger lever being movable into and out of the opening in the presser foot, means for oscillating the plunger lever, and means located between the presser foot and the standard fOI adjusting vertically the bodily position of oscillation of said plunger lever, said adjust- III combination with a frame inc uding a stand- 7 side ofthe'lowe-r arm.

ing meansbeing accessible from the under- 2. ha blind stitch sewing machine, the combination with a frame includinga standard and upper and lower arms, of a stitching head carried by the upper arm, a presser foot fixed to the stitching head and formed With a work receiving opening, an oscillatory plunger lever extending lengthwise within said lower arm and having its inner end pivoted thereto, the free end of the plunger lever being movable into and out of'the opening in'the presser foot, a fulcrum lever extending lengthwise of said lower arm below the plunger lever and having one end pivoted to said lover arm, means for oscillating'said plunger lever including a toggle connection between said ,plunger lever and said fulcrum lever, and means cooperating with said fulcrum lever for adjusting vertically the-bodily'position' of os-' .cillation of said plunger lever. Y '3. In a blind stitch sewing machine, the

combination with a frame including astandard and upper and lower ar1ns, of a stitching head carried by the upper arm,'a press er foot fixed to the stitching head and formed with aiwork' receiving opening,'an

oscillatory plunger lever extending lengthwise within said lower arm and, having its inner end pivoted thereto, the free end of the plunger lever being movable into and out of the opening inthe presser foot, a fulcrum lever extending lengthwise of saidlower' arm below the plunger lever and having its outer end pivotedto said lower arm,

means for oscillating said plunger-lever including a toggle connection between said plunger lever and said fulcrum lever, and

means cooperating with the inner end of.'

said fulcrum lever for adjusting vertically the bodily position of oscillation of said plunger leverge,

4. In ablindi stitchsewjng machine, the combination with a frame including a standard and upper and lower arms, a stitchmg head carried by the upper arm, a press-- or foot fixed to the, stitching head and formed with a work receiving opening, an

oscillatory plunger lever extending lengthwise within said lower arm and having its,

inner-end pivoted thereto, the free end of the plunger 'lever being inlovable into'andout of the opening in-the presser foot, a fulcrum lever extending lengthwise of said lower arm belowthe plunger lever and having its outer end ivoted to said arm, means for oscillating said plunger lever including v a toggle connectionv between said plunger lever and said fulcrum lever, a stop fixed to the lower arm and (:00 crating with the inner end 6f the fulcrum ever to limit theupward movement thereof, a spring connecting said lower arm and said fulcrum lever to yieldably hold the latter in engagement with said stop, and an adjusting screw carried bythefulcrum leverand engageable with said stop for varying the angular position of the fulcrum lever whereby the bodily position of oscillation of the fulcrum lever will be adjusted vertically. a, 5. In a blind stitch sewin .machine, the combination with a frame inc udingastandard and upper and lower arms, of a stitching head carried by the upper arm, a presser foot fixed to the stitching headand formed with a work receiving opening, an oscilla tory plunger ,lever extending lengthwise within said lower arm and having its inner end pivoted thereto, the free end of the plunger lever being movable into and out of the opening in the presser foot, a fulcrum lever extending lengthwise of said lower arm below, the plunger leven and having .one end pivoted to said lower arm, a toggle connection between said -plunger lever and, said fulcrum lever, a rotary main shaft journaled in the upper arm of the frame a vertically disposed cam shaft journaled .in said standard and operativel connected ed to the l with said main shaft, a cam lower end of said cam shaft, a link connectlon extending lengthwise of the lower arm between said toggle and said cam, and

means cooperating with said fulcrum lever for adJusting vertically the bodily position of oscillation of said plunger lever.

latory plunger lever extending lengthwise I 105' within said lower arm and having its inner end pivoted thereto, the free end of the plunger lever being movable into and out of the opening in the presser foot, a ,fulcrum lever extending lengthwise of, said A lower arm below the plunger lever having one end pivoted to said lower arm, a. toggle connection between said plunger lever and said fulcrum lever, and a cam controlled 4 means connected to said toggle for oscillating said plunger'lever.

7 In a blind stitch sewing machine the combination with a frame includin a stand-K ard and upper and lower arms, 0 a stitching head carried by the upper arm, a resse foot -fixed to the stitching head and ormed with a work receiving opening, an .oscillatory plunger lever extending lengthwise within said lower arm and having its inner end pivoted thereto, the free end 'of the plunger lever being movable into and out of the opening in the resser foot, a fulcrum lever extending engthwise of said lower arm below the plunger lever and havmg its outer end pivoted to said arm, a sto fixed to the lower arm and cooperating wit .ried by the fulcrum lever an ment with said stop, a toggle connection between said plungerlevei' and said fulcrum lever, a cam controlled means connected said toggle connection for oscillating said plunger lever, and an adjustin screw carengageable with said stop for varying the angular position of, the fulcrum lever whereb the bodily position of oscillation of the fu crum lever will be adjusted vertically. v 8. In a blind stitch sewing machine the combination with .a frame including a standard and upper and lower arms, of a stitching head carried by the upper arm, a resser foot fixed to the stitching head and ormed with a work receiving opening, an oseil latory plunger lever extendin lengthwise within said lower arm and having its inner end pivoted thereto, the free end of the plunger lever being movable into and out of the opening in the resserfoot, a fulcrum lever extending engthwise of said lower arm below the plunger lever and having its outer end pivoted to said arm, a stopfixed to the lower arm and cm ratingwith the inner end of the fulcrum ever to limit the upward movement thereof, a spring connecting said lower arm and said fulcrum lever to yieldably hold the latter in engagement with said stop, a toggle connection between said plunger lever and said" fulcrum lever, a rotary main shaft journaled in the upper arm of the frame, a vertically disposed cam shaft journaled in said standard and operatlvely connected with said main shaft, a cam fined toithe lower end of said cam shaft, a driving connection between said cam and said toggle for oscillating said plunger lever including a link extendinglengthwise of the lower arm, and means cooperating with said fulcrum lever for adjusting vertically the bodily position of oscillation of said plunger lever. 1 9. In a blind stitch sewing machine,the combination with a presser foot having a work opening, of a plunger lever fulcrumed below said presser foot and having its free end movable into' and out of the workopen- I ing of said presser foot, a fulcrum lever mounted below said plunger lever, a stop to limit the upward movement of said fulcrum lever, a toggle connection between said plunger lever and said fulcrum lever, means for actuating said to gle connection to oscillate said plunger ever into and out of the work opening of said presser foot, and a spring for normally holdin said fulcrum lever in engagement with sai stop. 1 0. In a blind stitch sewing machine, the combination with a resser foot having a work opening, of a unger lever fulcrumed below said presser oot and having its free end movable into and out of the work-opening of said presser foot, a fulcrum lever mounted below said plunger lever, a stop to limit the upward movement of said fulcrum lever, a toggle connection between said plunger lever and said fulcrum lever, means for actuating said toggle connection to oscillate said plunger lever into and out of the work opening of said presser foot, a spring for normally holding said fulcrum lever in engagement with said stop, and

means cooperating with said fulcrum lever and stop for vaying the "bodily position of said ever to a just the high point of oscillation of said plunger. lever.

In testimony whereo I hereunto affi; my.

signature.

I CHARLES W M'UELLER. I 

